Insulin increases shedding of syndecan-1 in the serum of patients with type 2 diabetes mellitus

Aims: To detect the level of serum syndecan-1 of patients with type 2 diabetes. Methods: Subjects with diabetes were categorized into 4 subgroups, oral-agents, insulin therapy for <= 1 month, 1-12 months, and >12 months. Serum syndecan-1 was detected by ELISA, and potential correlation between syndecan-1 levels and clinical characteristics was analyzed. Results: Sixty-two diabetic patients and 20 healthy subjects (controls) were enrolled. Syndecan-1 in diabetic patients (24.616 +/- 1.993 ng/ml) was higher than that of the controls (18.907 +/- 2.638 ng/ml). The average concentration of syndecan-1 in the group of oral-agents, insulin therapy for <= 1 month, 1-12 months, and >12 months was 19.157 +/- 2.556 ng/ml (n = 20), 24.447 +/- 3.173 ng/ml (n = 23), 35.005 +/- 4.749 ng/ml (n = 11), and 27.593 +/- 8.304 ng/ml (n = 8), respectively. An association between serum syndecan-1 and intake of exogenous insulin was found (r = 0.266, p = 0.035). Serum syndecan-1 of insulin-therapy group (27.811 +/- 2.669 ng/ml) enhanced significantly compared to that of the controls (p = 0.030) and that of the oral-agents group (p = 0.035). Syndecan-1 of the insulin therapy for 1-12 months group enhanced predominantly compared to that of the controls (p = 0.005) and the oral-agents group (p = 0.005). Conclusions: Chronic inflammation and exogenous insulin usage increases serum syndecan-1 level. Exogenous insulin can promote shedding of syndecan-1 ectodomains to the serum in a time-dependent manner. (C) 2009 Elsevier Ireland Ltd. All rights reserved.